Policykit adventures

After installing Debian on a laptop this week, once again, I ran into the “problem” of not being able to shutdown or reboot the computer, when another user is logged in, for example via SSH. If you’re a Linux user, maybe you have seen it:

System policy prevents restarting the system when other users are logged in

The cause of this behaviour is something called policykit, and a policy defined in /usr/share/polkit-1/actions/org.freedesktop.consolekit.policy. I found several pages on the web, that suggested to modify this file to change the policy. However, as this file is shipped by a package, and living below /usr/share, it is not intended to be modified by users to override the policies it contains.

The correct way to fix the problem is in something called PolicyKit Local Authority, or pklocalauthority. To enable all users to shutdown or reboot the computer, even when other users are logged in, create a file named /etc/polkit-1/localauthority/50-local.d/usershutdown.pkla (the name must end in .pkla) and put the following in it: